1. Field of the Invention
The invention relates to miniature microscope objectives, and particularly to miniature objective arrays for multi-spectral imaging.
2. Discussion of the Related Art
Miniaturization of microscope objective optics, e.g., to less than a few mm or less than around 5 mm in diameter, has many potential applications in imaging. It is the enabling technology for the construction of a microscope array such as the miniature microscope array (MMA). Moreover, miniature microscope objective designs for MMA have certain characteristics that are uncommon from typical microscope objectives.
Imaging in multiple spectral bands is extremely useful in microscopy applications. For example, to construct a color image of an object for visual inspection, it is desired to image the object at multiple wavelength bands, and preferably at three spectral bands corresponding to red, green, and blue. For non-visual inspection, it may be advantageous to image the object at different or additional wavelengths even including non-visible wavelengths, and perhaps at more than three spectral bands determined by the object's material properties.
A MMA includes many miniature microscope objectives. Each one of MMA's individual microscope objective forms a 2D image. MMA preferably is used as a scanning system, and so a thin, substantially linear portion of an entire 2D image is used as an object is scanned. In this case, the rest of the image is not used.
It is recognized in the present invention that one can take advantage of this situation by scanning the object at different spectral bands simultaneously or substantially simultaneously. For example, multiple linear detectors equipped with different spectral filters may be used to simultaneously image an object at multiple spectral bands. The number of spectral bands imaged may depend on the size of the 2D images and the area of the available image field, i.e., how many linear detectors can fit in that image field.